Who art thou? — This is addressed to the weak. The Apostle indignantly challenges his right to judge. That right belongs to another tribunal, before which the conduct of the stronger Christian will not be condemned but approved and upheld.
He standeth or falleth. — It seems most in accordance with what precedes to take this of judicial condemnation or approval from the Master whom he serves — i.e., Christ.
Holden up. — The same word as that in the clause following, and similar to that in the clause preceding — “Made to stand.”
God is able to make him stand. — The true reading here is “the Lord” — i.e., Christ; the word is the same as “his Master” above. “Make him stand” seems to be still judicial. “Secure his acquittal,” but with reference to his previous course of conduct on which that acquittal is grounded. The trial is not necessarily reserved for the last day, but is rather the judgment which Christ may be supposed at any moment to pass upon His servants. If they can sustain this judgment, it is only because His grace has enabled them so to act as not to be condemned by it.